The present invention concerns an apparatus for balancing vehicle wheels in accordance with the classifying portion of claim 1.
An apparatus of that kind, which is known from German utility model No 16 96 373, serves for compensating for unbalance of vehicle wheels by fitting balancing weights. That can involve for example wheels of motorcycles, automobiles, trucks etc. In order to be able to implement the wheel-balancing operation the vehicle wheel to be balanced is clamped on the main shaft of the apparatus. The wheel is then set in rotation and at least one location for fitting a balancing weight to the wheel is ascertained. After the weight has been fitted the freshly balanced wheel is removed from the apparatus. Such apparatuses have a guard hood to prevent fouling of the workshop and injury to the operator while the main shaft and the wheel clamped thereon are rotating. In the known apparatus the guard hood comprises a guard hood element which is stationary, being fixedly connected to the foundation structure of the machine, and a movable guard hood element which is reversibly movable between an operative position and an inoperative position along an arcuate guide afforded by the stationary guard hood element. The arcuate guide is formed by grooves along which the movable guard hood element is slidably guided.
In an apparatus which is known from EP 0 767 364 A1, the guard hood comprises a stationary guard hood element rigidly mounted to the machine frame structure and a movable guard hood element reversibly movable from an inoperative position in which the wheel can be fitted on the main shaft and removed therefrom, into the operative position. In the operative position, the movable guard hood element in conjunction with the stationary guard hood element extends around the vehicle wheel along the tread surface thereof, through more than 180xc2x0 C. The movable guard hood element is arranged in relation to the stationary element, on the side thereof which faces away from the main shaft, and it can be pivoted into its two positions by means of a pivot lever which extends substantially parallel to the main shaft and which is mounted to the machine frame structure. The presence of the additional pivot lever means that this arrangement is comparatively complicated and expensive, both in terms of the material used and also in terms of manufacturing and assembly costs.
A further problem in connection with apparatuses of the above-indicated kind is that, when the operator is rotating the wheel to be balanced into the respective position for balancing thereof, the operator must continuously observe an operating and display unit which inter alia shows the direction of rotation of the wheel to move it into the balancing position. In the case of the previously known apparatuses for example EP 767 364 A1, EP 557 240 B1 or DE 85 17 924 U1, that operating and display unit is arranged on the machine frame structure in such a way that an operator is required to turn his head when working on the wheel. That is unsatisfactory from ergonomic points of view and can also result in defective operation of the apparatus.
The object of the present invention is to provide an apparatus of the above kind, which ensures ergonomically appropriate operation thereof.
That object is attained by the features of claim 1. Advantageous configurations are set forth in the following claims.
For that purpose the operating and display unit is disposed at the end of the stationary guard hood element, which faces to the operative position of the movable guard hood element. The operating and display unit may include at least a monitor and at least one or more operating elements.
Advantageously the operating and display unit is arranged in the direction of view of the operator, that is to say radially relative to the main shaft, directly on the guard hood. The operating and display unit is arranged on the stationary guard hood element in such a way that the movement of the movable guard hood element is not impaired thereby. That can therefore provide an ergonomically appropriate structure for the location of installation of the operating and display unit, which was not possible in the use of the previously known apparatuses.
It is advantageous if the movable guard hood element is mounted movably to the stationary guard hood element by way of a guide means, in order thereby to ensure reliable and safe movement of the movable guard hood element while also ensuring that the apparatus overall is of a compact structure.
The guide means can be of any design configuration and adapted to the specific needs involved. A particularly advantageous structure provides that the guide means is formed by at least one guide rail mounted to the movable guard hood element and at least one guide roller mounted to the stationary guide hood element and in contact or engagement with the guide rail. In that case for example the guide rail can be disposed approximately in the middle of the movable guide hood element and the guide roller can also be disposed in the middle of the stationary guide hood element. The guide rail can then be of an L-shaped cross-section, in which case the at least one guide roller and more particularly two guide rollers roll on the substantially horizontally extending limb of the L-shape of the guide rail.
In principle the guide roller can be arranged at any suitable location on the stationary guard hood element. A particularly compact and easily maintainable structure for the guide hood can be achieved if the guide roller is arranged at the end of the stationary guard hood element, which faces to the operative position of the movable guard hood element.
As has already been noted above, the guide means can be formed from at least one guide rail and at least one guide roller. To ensure a secure guidance effect and thus good operability, it is advantageous for the guide means to comprise two guide rails which are respectively mounted to edges of the movable guide hood element, which edges extend in the direction of movement of the movable guard hood element, and includes eight guide rollers of which four are respectively arranged in pairs on each of the two edges of the stationary guard hood element, those edges extending in the direction of movement of the movable guard hood element. To reduce the risk of injury to the operator, it is possible to provide in the region of the guide roller or rollers a cover means, for example in the form of a rail which extends perpendicularly to the guard hood element, or a like portion of sheet metal.
The guide means and more particularly the guide rollers of the guide means can be provided at the inwardly facing side of at least one guard sheet metal strip at the upper end of the stationary guard hood element. The guard strip can extend around the path of movement of the movable guard hood element. Preferably, guard strips bearing the guide rollers provided at the inward sides are arranged at both sides of the upper end regions of the stationary guard hood element.
It can further be provided that the movement of the movable guard hood element from the inoperative position into the operative position and vice-versa is limited by abutments in order to be able securely to define the limit positions of the movement of the movable guard hood element, that is to say the inoperative position and the operative position respectively thereof.
To facilitate handling of the apparatus on the part of the operator, the apparatus in accordance with the invention is provided with at least one weight-compensating device for the movable guard hood element.
In order to ensure reliable guidance for the guide roller on the guide rail, the guide roller may be provided with a guide profile, more particularly a guide groove by means of which it is in with the guide rail. If the guide means includes a plurality of guide rollers, preferably all guide rollers at an edge of the stationary guard hood element also provided with guide grooves.
The shape of the two guard hood elements can be adapted to the respective circumstances. A particularly appropriate and compact shape is achieved if the two guard hood elements are each in the form of a segment of a circle or an arc with at least approximately equal radii of curvature.
As in particular the operator is intended to be protected by the guard hood and as moreover the movable guard hood element faces towards the operator in operation of the apparatus, it is further advantageous, to ensure that the operator is safely protected, if the movable guard hood element is of a greater width as measured approximately transversely with respect to its direction of movement, than the stationary guard hood element.
In order that the movable guard hood element can be moved from the inoperative position to the operative position and vice-versa by the operator, it is further advantageous if a gripping bar is mounted to the end of the movable guard hood element, which end faces towards the operative position thereof. The gripping bar preferably extends transversely with respect to the direction of movement.
In addition a telescopic bar may be pivotably mounted to the end of the movable guard hood element, which faces towards the operative position, while the second end of the telescopic bar is pivotably mounted to the stationary guard hood element. In that arrangement, the pivotable mountings may be such that the telescopic bar is mounted to the stationary guard hood element such that it extends substantially horizontally when the movable guard hood element is in the operative position.
The telescopic parts of the telescopic bar, which are in telescoping relationship with each other, can be subjected to the force of a spring member and the action of a damping member. That can provide a weight-compensating effect for the movable guard hood element. That also provides for absorbing shock loadings or impacts in the movement, more particularly in the respective end positions of the guard hood element.
The telescopic bar however may also be a carrier for devices for measuring distance and diameter, in the form of sensing levers or sensors which measure in a contact-less mode. That makes it possible to easily determine the respective type of wheel or wheel rim involved, and to implement subsequent setting of the measurement and evaluation unit of the balancing machine.
In addition, when the guard hood is closed, the telescopic bar can afford protection to prevent a person from reaching into the wheel which rotates in the measuring operation. It is also possible for that purpose to provide a cover in the region of the clamping device with which the wheel to be balanced is clamped on the main shaft.
In order to make it easier for the wheel which is to be balanced to be mounted on and removed from the main shaft, the apparatus may further include a ramp at the bottom of the machine support structure, so that a vehicle wheel can be rolled up and down the ramp.
Further advantageous configurations and an embodiment by way of example are described hereinafter with reference to the accompanying drawings. In this connection it is to be noted that the terms used in the description hereinafter xe2x80x98downxe2x80x99, xe2x80x98upxe2x80x99, xe2x80x98leftxe2x80x99and xe2x80x98rightxe2x80x99 relate to the drawings with the legends legible in the normal fashion.
FIG. 1 is a diagrammatic perspective view of an apparatus according to the invention showing a movable guard hood element in an inoperative position,
FIG. 2 shows a diagrammatic perspective view from below of a stationary guard hood element of the apparatus shown in FIG. 1, with guide rollers mounted thereto,
FIG. 3 shows the guide rollers of FIG. 2 in the condition of engagement with a guide rail mounted to the movable guard hood element of the apparatus of FIG. 1,
FIG. 4 shows a diagrammatic perspective view from below of the stationary guard hood element with further guide rollers arranged on the side of the stationary guard hood element, which is opposite to the side shown in FIGS. 3 and 4,
FIG. 5 shows a diagrammatic perspective view of the guide rollers illustrated in FIG. 4 in the condition of engagement with a guide rail mounted to the movable guard hood element,
FIG. 6 shows the apparatus of FIG. 1, with the movable guard hood element in the operative position, and
FIG. 7 shows a view from the front of an embodiment using the guide rollers shown in FIGS. 2 and 4.